811044821 has 4 divisors (see below), whose sum is σ = 830826444. Its totient is φ = 791263200.

The previous prime is 811044809. The next prime is 811044833. The reversal of 811044821 is 128440118.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (811044809) and next prime (811044833).

It can be written as a sum of positive squares in 2 ways, for example, as 281400625 + 529644196 = 16775^2 + 23014^2 .

It is a cyclic number.

It is not a de Polignac number, because 811044821 - 2¹⁴ = 811028437 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (811044881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9890750 + ... + 9890831.

It is an arithmetic number, because the mean of its divisors is an integer number (207706611).

Almost surely, 2^811044821 is an apocalyptic number.

It is an amenable number.

811044821 is a deficient number, since it is larger than the sum of its proper divisors (19781623).

811044821 is a wasteful number, since it uses less digits than its factorization.

811044821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19781622.

The product of its (nonzero) digits is 2048, while the sum is 29.

The square root of 811044821 is about 28478.8486600143. The cubic root of 811044821 is about 932.5703822656.

Adding to 811044821 its reverse (128440118), we get a palindrome (939484939).

The spelling of 811044821 in words is "eight hundred eleven million, forty-four thousand, eight hundred twenty-one".